They are terrestrial gastropod mollusks in the family Testacellidae, the shelled slugs.

"Have You Seen A Shelled Slug Called Testacella!"

Testacella scutulum is an air-breathing, carnivorous land slug, a terrestrial gastropod mollusk in the family Testacellidae, the shelled slugs.

The Santa Barbara shelled slug or slug snail, scientific name Binneya notabilis, is a species of air-breathing land slug, a shell-less terrestrial gastropod mollusk in the family Binneyidae.

"A predatory (shell) slug (Testacella haliotidea)"

The shelled slug, scientific name Testacella haliotidea, is a rarely seen, air-breathing, carnivorous land slug, a terrestrial gastropod mollusk in the family Testacellidae, the shelled slugs.